The present invention is directed to the field of heating ducts. More particularly, the present invention is directed to duct boots, connectors and the like, made of plastic. This invention is related to jointly owned U.S. Pat. No. 6,196,597 entitled “Heating Duct”, which is hereby incorporated by reference.
The majority of duct being installed in residential and commercial units is fabricated of sheet metal, although, recently, flex duct has become more widely used. Metal ducts pose a number of problems. First, when the duct is cut to length, the end is razor sharp and poses a handling hazard. Secondly, metal is a good conductor of heat (and electricity) and without insulation, the metal duct will lose a considerable amount of heat to an uninsulated air space. Insulating the duct is an expensive alternative, although a prudent building owner will recoup the expense over time in energy saved, especially given the projected short-term increase in fuel costs.
Thirdly, metal fittings are difficult to seal properly. The use of mastics and tapes are needed to seal the joints to prevent and overcome the excessive leaks due to metal on metal connections. Any denting of the metal further exacerbates the problem of sealing the connection. The process of using the mastics is messy and both the taping and mastic application are time consuming.
The present invention overcomes the deficiencies of metal ducts. Plastic duct is safer to handle, having no razor sharp edges. Further, plastic is a poor conductor of both heat and electricity, significantly reducing the btu's lost through the walls of the connectors. Further, tolerances on the plastic ducts can be held tighter and, plastics are not prone to denting, so junctions form tighter seals resulting in reduced air and heat loss at the junctions.
Various other features, advantages and characteristics of the present invention will become apparent to one of ordinary skill in the art after a reading of the following specification.